Conductor for radio frequency currents



July 5, 1938. H. o. ROOSENSTEIN CONDUCTOR FOR RADIO FREQUENCY CURRENTSFiled July 8, 1953 INVENTOR HANS OTTQ RQQSENSTEIN BY /%W ATTORNEYPatented July 5, 1938 PATENT OFFICE CONDUCTOR FOR RADIO FREQUENCYCURRENTS Hans Otto Roosenstein signor to Telefunken lose Telegraphie m.b.

, Berlin, Germany, as- Gesellschaft fiir Draht- 11., Berlin, Germany, a

corporation of Germany Application July 8, 1932, Serial No. 679,505 InGermany August 12, 1932 13 Claims.

This invention relates to high frequency electric conductors and radioaerials.

is useful for various purposes in the high frequency art, andparticularly for aerials, to have available, conductors which are inappearance of approximately cylindrical or rod-like form but have theelectrical properties of much more complicated electrical structures.The current duct curr distribution over such specially formed conors canbe made entirely different from the ent distribution along a simplecylindrical conductor and by employing. such conductors it it possibleto obtain in the case of a conductor carrying high frequency energy,special radiation properties, different from those of an ordinaryconductor and of an advantageous nature for practical purpose canMoreover, such conductors d to constitute a semi-shielded s. beconstructe conductor for high frequency alternating current s and yet beof simple mechanical form.

The various forms of recesses are shown by the accompanying drawing, in.which:

Fig. 1 shows a cross-secti onal View of a solid conductor havingrecesses at equal distances alon Fi g its length; g. 2 indicates across-sectional view of a composite conductor of insulating andconducting material;

g. 3 is another embodiment of a composite conductor tribution of currentalong the condu g. 3a is a graphic representation of the disctor; whileg. 31) is a graphic representation of the distribution of current alongthe conductor when the outer conductor is the medium for thedisdecimeter waves. current distribution on the con A decisiveinfluencing of the ductor occurs if the electrical length of therecesses below the general of magnitude of half the ing frequency. Thiscan surface of the conductor is of the order wave length of the workbeattained while retaining relatively small recesses, by filling in thesaid recesses completely or par tially with insulating material. Theeffectiveness of such an arrangement may be still further increased byadmixing with the insulating filling material a finely subdividedmagnetizable substance, e. g. iron powder.

g. 2 shows in section an arrangement of this kind and in which there isemployed a central conducting rod Z over which are pushed structures P,Q and R, consisting of spaced hollow formed tubes, as shown leavingrecesses which are completely or partially filled up with insulatingmaterial J which may have powdered iron of magnetic materialincorporated therein. Such a conductor or lead, consisting as it does ofa large number of sections which can be assembled together, has theadvantage of being easy to, construct in practice. The properties ofsuch a line when feeding high frequency alternating currents can becontinuously varied and adjusted in a very simple manner if theinsulating filling material contains a magnetic substance whosepermeability is a function of the magnetic field therethrough by passingthrough the line a variable direct current which produces an adjustablemagnetic field in the said magnetic material. In particular, where aconductor as illustrated in Fig. 2 is employed as an aerial (animportant application) the. above described method of varying thealternating current properties of the conductor can with advantage beused to vary the radiation diagram of the aerial when used on a givenwave length or to obtain a predetermined radiation diagram withdifferent wave lengths. This is of particular advantage where theconductor is employed in a directional aerial system for the lineardimensions of the system can remain unchanged and yet the system can beused over a fairly wide range of wave lengths without substantialdeterioration of the directional diagram or characteristic. It will nowbe explained what form the current distribution or the directionaldiagram assumes with different lengths for the" recesses of a conductoras shown in the accompanying Fig. 3 when said conductor is employed in adirectional transmitting or receivingaerial system. Fig. 3 shows aconductor similar to that of Fig. 2 but with unfilled recesses, i. e.the material J is omitted.

If the electrical length Z of that portion of the recess which liesbelow the general surface of the conductor is slightly smaller than halfthe wave length of the working frequency and the length L of conductorbetween adjacent recesses (see Fig. 3) is slightly larger than the halfwave length there is then produced on the aerial a current distributionsubstantially as shown by the curve K in Fig. 3a. The currents in thelengths between recesses are as will be seen in substantially the samephase at corresponding points in the length of the conductor, so thatwith such an arrangement sufficiently long relative to the working wavelength a sharp concentration of radiation is obtained. A sharpconcentration is also obtained if the electrical length of the recessesis made somewhat larger than the half wave length. In this case, thecurrent distribution will be as shown by the curve K of Fig. 3b, and aswill be obvious to those skilled in the art, such a current distributioncurve is still more favorable for the concentration of radiation. Thecurves V in Figs. 3a and 3b show the corresponding voltage distributionsand it will be seen that there is a voltage node at the middle of eachconductor member. In order to avoid losses in terminals, insulators andsupports (not shown) for the conductor the said insulators or terminalsare preferably fitted at voltage nodal points.

I claim:

1. An antenna for extra short electrical magnetic waves, comprising arod-like conductor having recesses below the surface of said conductor,said recesses being spaced at not less than onehalf the working wave,said recesses partly filled with insulating material to increase themechanical strength of said antenna.

2. An antenna for extra short electrical magnetic waves, comprising arod-like conductor having recesses below the surface of said conductor,said recesses being located at not less than one-half the working wave,said recesses partly filled with insulating material containing a finelydivided magnetizable substance.

3. An antenna for extra short electrical magnetic waves, comprising arod-like conductor hav ing recesses below the surface of said conductor,said recesses being located at not less than onehalf the working wave,said recesses partly filled with insulating material containing a finelydivided magnetizable substance, the permeability of the magnetizedsubstance being variable so that the radiation diagram of the antennaand the line impedance for radio frequency currents is variable.

4. An antenna rod-like conductor for radiofrequency currentscharacterized by recesses which are formed as equally spaced slots inthe solid material of said rod-like conductor, said recesses being atright angles to the axis of said conductor and located at not less thanone-half of the working wave.

5. A rod-like conductor for short decimeter electrical magnetic wavescomprising a conductor having a plurality of rods with annular recesseslocated on said conductor, said annular recesses being located andspaced apart from each other at one-half the Wave length used on saidconductor.

6. A rod-like conductor for short decimeter electrical magnetic wavescomprising a conductor having a plurality of tubes of conductingmaterial having annular recesses equally spaced with a plurality ofinsulating members, said tubes and insulating members being located onsaid conductor and spaced apart from each other at one-half the wavelength used on said conductor.

7. A rod-like conductor for short decimeter electrical magnetic wavescomprising a conductor having annular recesses below the surface of saidconductor, said annular recesses being located at not less than one-halfthe wave length used on said conductor, said annular recesses filledwith insulating material containing a magnetizable substance, thepermeability of the magnetized substance being varied by passing throughthe conductor a variable direct current which pro duces an adjustablemagnetized field in,- said magnetized substance in order that theradiation diagram of the conductor impedance for radio frequency currentis variable.

8. A rod-like conductor for high frequency currents having a pluralityof annular recesses located at predetermined electrical points on saidconductor, said predetermined points being equal to one-half the wavelength used on said conductor.

9. A rod-like conductor according to claim 8 comprising insulatingmembers located at voltage nodal points on said conductor.

10. A rod-like conductor for high frequency currents having a pluralityof annular recesses located at predetermined electrical points on saidconductor, said predetermined points being equal to one-half the wavelength used on said conductor, said annular recesses being filled withiron powder.

11. A rod-like conductor for high frequency currents having a centralconductor, a plurality of tubular conductors and insulating membersalternately arranged on said central conductor, said tubular conductorsand insulating members being spaced apart from each other atpredetermined electrical points on said central c0nductor.

12. A rod-like conductor for high frequency currents having a centralconductor, a plurality of tubular conductors and insulating membersalternately arranged on said central conductor, an annular recess onsaid insulating members, said tubular conductors and insulating membersbeing spaced apart from each other at predetermined electrical points onsaid central conductor.

13. A rod-like conductor for high frequency currents having a centralconductor, a plurality of tubular conductors and insulating membersalternately arranged on said central conductor, an annular recess onsaid insulating members filled with iron powder, said tubular conductorsand insulating members being spaced apart from each other atpredetermined electrical points on said central conductor.

HANS OTTO ROOSENSTEIN.

